Quite possibly the greatest game of all time, the original Deus Ex is a masterpiece of a game. For only 7 dollars it's an easy recommendation, and while some of the more dated UI elements may take some time to get used to it's aged incredibly well in terms of most other things. If you have even the slightest interest in the genre of cyberpunk, or in the immersive sim style of games, this game is the gold standard for both of those in gaming. In my experience the steam version runs fine on modern systems, though as usual with games this old your experience may vary - it's absolutely worth the effort to get running smoothly.